Track driven vehicles are commonly used in the agricultural and construction industries. Track driven vehicles are commonly very heavy vehicles that require a substantial load to be carried by each track and track suspension on the vehicle. For this reason, prior art suspensions have minimal travel and articulation to idler and roller wheels in contact with the track. The lack of articulation of the idler and roller wheels limits the tractive force of the track and also causes forces to be transmitted to the vehicle from the idler and roller wheels. This lack of articulation can make the ride less comfortable for the driver of the track driven vehicle and in some cases can lead to excessive vehicle part wear.
U.S. Pat. No. 3,841,424 discloses a vehicle supporting and driving assembly for a vehicle having an axle housing and a drive axle in the axle housing comprising: a main pivot shaft securable to said axle housing, a track frame having an intermediate point secured to the main pivot shaft for pivotal oscillation of the track frame with respect to said axle housing, and having first and second ends extending from said intermediate point, idler support members at the first and second ends of the track frame, means pivotally and reciprocably securing the idler support members to the track frame ends, idlers rotatably mounted on the idler support members, cushion means responsive to reciprocation of the idler support members with respect to the track frame ends to cushion recoil of the idlers, a rotatable drive sprocket attachable to said axle housing and positioned between the ends of said track frame and above the idlers, means driving the rotatable drive sprocket by the drive axle, and a track chain encompassing the idlers and drive sprocket and in driven engagement with the drive sprocket.
U.S. Pat. No. 5,842,757 discloses a track suspension apparatus for a vehicle of a type having a powered drive shaft for rotation about a drive axis, comprising:
a frame operably pivotably attached to said vehicle drive shaft; a continuous flexible track; a drive wheel adapted to be attached to a vehicle and operatively and rotatably attached about said drive axis to said frame for engaging and driving said continuous flexible track; and an undercarriage mounted to said frame, said undercarriage including at least two leading equalizers and two trailing equalizers, the leading and trailing equalizers being independently-pivotable on said frame, each leading equalizer having leading and trailing front idler rollers rotatably attached thereto in fixed relative positions and each trailing equalizer having intermediate rollers and trailing rear idler rollers rotatably attached thereto, the rear idler rollers being rotatable attached to a trailing arm and the intermediate rollers being rotatable attached to an intermediate-roller mounting plate which is pivotably mounted with respect to the trailing arm said idler rollers being in engagement with said track.
U.S. Pat. Re. No. 36,284 discloses a track suspension apparatus for a vehicle having a frame, comprising: a continuous flexible track; a drive wheel operatively attached to said frame for engaging and driving said continuous flexible track; a leading idler arm operatively pivotally attached to said frame; a leading idler wheel in engagement with said track and rotatably mounted to one end of said leading idler arm; a trailing idler arm operatively pivotally attached to said frame; a trailing idler wheel in engagement with said track and rotatably mounted to one end of said trailing idler arm; a mid-roller assembly in engagement with said track and operatively attached to one of said idler arms; an interconnecting structure for holding said leading and trailing idler arms in a predetermined position; and cushioning means associated with said interconnecting structure for providing a shock absorbing function when said leading and trailing idler wheels move with respect to each other due to pivoting of said idler arms when irregular surfaces are encountered by said track, said cushioning means comprising a fluid control device operably attached at one end thereof to one of said idler arms and operatively attached at the other end thereof to the other one of said idler arms.
U.S. Pat. No. 5,316,381 discloses a hydraulic tensioning and suspension system having a main drive wheel located above and between two idlers that are mounted to pivot arms that are coupled to a rigid frame. In this hydraulic tensioning and suspension system two track rollers are mounted to the rigid frame by an intermediate arm and a third track roller is mounted to the front pivot arm by an additional pivot arm. Four hydraulic suspension cylinders are hydraulically coupled to one another for biassing the idlers and track rollers downwardly to provide a suspension system. The rear pivot arm is a telescoping arm having a hydraulic tensioning cylinder. A two position control valve supplies hydraulic fluid to the hydraulic tensioning cylinder in response to a speed ratio selected by the operator. With higher tension being applied to the track when the vehicle transmission is in low gear and lower tension is being applied to the track when the vehicle transmission is in higher gears.
U.S. Pat. No. 5,340,205 discloses an active suspension system for a tracked vehicle having a main drive wheel and two idlers which are surrounded by a track. The suspension system is provided with a walking beam that is pivotally mounted to the supporting structure of a vehicle by a walking beam pivot. The beam has a first section and a second section. An angled first arm is pivotally coupled to the first section of the walking beam and to which the first idler is rotatably mounted. A second telescoping arm is pivotally mounted to the supporting structure at the walking beam pivot to which the second idler is rotatably mounted. Three track rollers are operatively coupled to the angled arm by an angled link. Two of the track rollers are rotatably mounted to a bridging member which is pivotally coupled to the first arm of the angled link. The third track roller is rotatably mounted to the second arm of the angled link.